AVO Shocks Settings....?

[V8Smith]

Having found out my settings are all wrong yesterday just wondered if anyone knew the correct settings for a V8S, any suggestions GreenV8S? Is there an ideal position for the Spring seat height from the collar? and what setting should I set them at, they are set at 8 back and front, at the moment?

Much appreciated.

Mike

[joospeed]

what do u mean your settings are all wrong?

[M@H]

The spring seat setup on the car in question is about right at the back in that the height looks OK, and the seat is 12mm from bottom of the threads. The only minor snag being that when unloaded, the spring is about 1" short and falls out of the top seat.

The front spring seat is about 15mm up the threads (on average) and IMO could be a bit low.. on cornering, the wheel looked dangerously close to the bonnet wheelarch.. I think this could be helped with harder springs mind you as ultimately thats all that will change the "roll" of the front of the car.

By set up wrong.. the problem with the car is that it has been corner weighted at some time with a "large" (I guess) driver seated in it and the original difference in thread height was 12mm left to right (drivers side being higher of course) rear and looked more like 15mm+ at the front.

Basically the car needs corner weighting again as we set the rear to neutral (on discovering the imbalance) but didn't get a chance to sort the front out, then Damper settings can be trialed.. 8 (of 15) was chosen as a sporty middle ground.

I'm my mind I'd get springs you are happy with (and you may well be happy with the ones you have ), get it corner weighted with you in it or set it to neutral if you are going to drive it quite a bit "two-up", then worry about the clicks on the Dampers.

Cheers
Matt

>> Edited by M@H on Thursday 24th June 12:11

[HarryW]

Matt are you stating your settings there or V8smith's car .
I know Joolz has a lot of recent experience with his own V8S on track days and has alot to offer. As does PeterH.
I'm a little surpised if those figuresare for Mikes V8S as it was sprint prepared before he bought it, or have things changed since .
Mine, whilst stil not fully set up (when is it ever ) and it is pretty awesome to me, Nitrons to PeterH's spec (short stroke) and 475/375 front/rear springs. However the spirng rates are marginaly too harsh if is is only a B road/rough road car .
I run the Nitrons at present at 5 clicks from softest at the front and 3 at the rear for normal road use(out of a max of 22 turns). For spirited driving this goes up to 12/10 on the road and believe me it is 300% better than standard .

Harry

>> Edited by HarryW on Thursday 24th June 12:29

[shpub]

V8Smith said:

Having found out my settings are all wrong yesterday just wondered if anyone knew the correct settings for a V8S, any suggestions GreenV8S? Is there an ideal position for the Spring seat height from the collar? and what setting should I set them at, they are set at 8 back and front, at the moment? Much appreciated. Mike

No. The spring seat should be in a position that the spring does not come unloaded on full droop or hit the bumpstop on full bump. Between those two positions is fine. The next question is to set the coil height so that weight is balanced which comes back to cornerweighting.

[bridgdav]

Matt is quoting mikes set up...

Being there yesterday, Andrew from 1st lotus noticed it when he drove it for the first time... the back end was very tail happy and the balance of the car was all wrong when he exceeded any sort of limit...

[joospeed]

there's a lot going wrong here .. basically either you're running springs which are very stiff, or you have too long a stroke on the damper, or both.

seeing as the rear is tail happy i'd go with too high a spring rate, do you know what rates you're running .. I have this problem on my S avos but I have 650 front/450 rear so i expected it. On the avo you can't change any specs on the std dampers .. I run rear cerbera dampers all round on my S but have the same issue you have, plus I run mine incredibly low.

Best bet is to get the car to anyone who knows AVO dampers and carries a lot of springs in stock to get the set up right.

[V8Smith]

HarryW said:

I'm a little surpised if those figuresare for Mikes V8S as it was sprint prepared before he bought it, or have things changed since .

You and me both Harry, I assumed (wrongly) the guy had it set up correct as it had been used in the British Speed championships. I havent changed anything so it must be how he set it up!

At least now I know I can set it up properly and have it corner weighted.

Any advice would be appreciated, point noted Steve, thanks.

Cheers

Mike

[shpub]

M@H said:

The spring seat setup on the car in question is about right at the back in that the height looks OK, and the seat is 12mm from bottom of the threads. The only minor snag being that when unloaded, the spring is about 1" short and falls out of the top seat.

That is not good at all. It is not a minor snag at all. You either need to fit a spacer spring to keep everything in place or look at the spring lengths etc and calculate what you need.

You may not be able to run at the height you want without changing the shocks because the open and closed lengths of the shocks define the bump and droop positions of the suspension. If they are long then the spring has to be long enough to cover this and its spring weight set so that it will compress under the car's weight to give the ride height you want.

With a shorter stroke, spring rates can be increased to control the amount of movement due to weight transfer and this allows you to define the amount of body movement and thus keep it between the required measurements.

If you want a 2 inch gap between the wheel and the wheel arch (example) then in the worst case weight transfer, the springs should only compress 2 inches (slightly less in reality). This defines the spring rate required. I would go measure what the shock open/closed lengths are and see how much off the bump stop you would be at the required ride height and then see how much movement you have.

I suspect that the shock open/closed length is not set up for the ride height you want. Set it to that height and the spring becomes unloaded. Stop that and the ride height is too high.
Going to a longer spring will mean that the spring will be loaded all the time but the gap will not happen and as weight is placed on the spring, the ride height will be higher. Fit a shorter spring and the unloading happens earlier.

I think what I am saying is go measure full bump and full droop and see what the shock's open/closed measurements is. Calculate what the shock length needs to be for the ride height and then see where that. I am guessing that it will be very close to the bump stop.

[V8Smith]

joospeed said:

there's a lot going wrong here .. basically either you're running springs which are very stiff, or you have too long a stroke on the damper, or both. seeing as the rear is tail happy i'd go with too high a spring rate, do you know what rates you're running .. I have this problem on my S avos but I have 650 front/450 rear so i expected it. On the avo you can't change any specs on the std dampers .. I run rear cerbera dampers all round on my S but have the same issue you have, plus I run mine incredibly low. Best bet is to get the car to anyone who knows AVO dampers and carries a lot of springs in stock to get the set up right.

It does sound like too long a stroke on the damper as like Matt said when the car is jacked up it is not sitting in the seat, but about an inch too short! Thanks for the advice I will get them checked out!

Cheers

Mike

[joospeed]

you're almost right in what you say steve, but you're approaching it from the wrong end .. you need to determine the spring rate you want for the handling / ride compromise you're after, then get the damper lengths to suit .. putting longer springs on won't sort the handling problem if the rate is too stiff, you just raise the ride height for any platform heing, and you'd only stop the unloading on the free spring if you ran with the seat at the botom of it's adjustment, otherwise you can just wind the spring seat down and unload the spring again ..

if you have the spring rates you want then the only choices you have are to have shorter stroke dampers or use a very light helper spring to take the clearance on full droop.

[V8Smith]

How can I find out what the spring rate is, is it written on the spring or am I going to have to try and speak to the last owner to find out what he fitted?

Cheers

Mike

[shpub]

joospeed said:

you're almost right in what you say steve.

All depends on what the priority is... You're right in that where I started from is not the only place to begin with... I tend not to consider ride quality a high priority for some reason.

I did end up making a simple computer model that allowed to play what if games and try different combinations of shock size, spring rate and so on.
Tried a lot of different approaches before finally deciding.

As for spring rates quite a few spring rate calculators on the web that take the physical dimensions and give you a good idea. Pretty good for single rate springs.

[M@H]

The actual poundage of the springs didn't look too bad on the track, certainly at the rear.. if I had to commit, I'd say the front was too soft though.

Steve, Re the spring falling out of the seat.. "minor snag" was an understatement and my "turn of phrase" so-to speak . It should fail any MOT like this for starters.. I suppose what I meant is that its not going to break anything driving it about normally like that, but should get looked at soon.

Cheers
Matt.

[shpub]

Arrrr... I understand now. THAT type of minor snag..

[M@H]

shpub said:

Arrrr... I understand now. THAT type of minor snag..

Indeed...

[andyf007]

My car has the Gaz setup spec'd by TowerView and comes complete with 'minor snag'. To prevent the spring dropping out of the seat would require either a very high ride height indeed (8" chassis to ground) or a much shorter damper length. Are we saying that TowerView (and others) are not selling the right kit

Andy

[M@H]

andyf007 said:

My car has the Gaz setup spec'd by TowerView and comes complete with 'minor snag'. To prevent the spring dropping out of the seat would require either a very high ride height indeed (8" chassis to ground) or a much shorter damper length. Are we saying that TowerView (and others) are not selling the right kit Andy

Do you have some retaining clips or something to hold the springs in place..? Seriously I'm certain its an immediate MOT fail if they come out of the seats when the suspension is unloaded.

Cheers,
Matt

PS. I trust you are doing PistonFest Andy.. ?

[joospeed]

andyf007 said:

My car has the Gaz setup spec'd by TowerView and comes complete with 'minor snag'. To prevent the spring dropping out of the seat would require either a very high ride height indeed (8" chassis to ground) or a much shorter damper length. Are we saying that TowerView (and others) are not selling the right kit Andy

I would say it probably needs further investigation ..

[shpub]

Just looked this up on the MOT Manual website...

"Take care when jacking vehicles with shortened or lowered springs fitted. Provided the spring ends locate correctly when the vehicle is lowered into the normal running position, without assistance this is not a reason for rejection."